Looking for a UPS Design That Doesn't Overheat Batteries

[Roy L. Fuchs]

Lye is worse, but you still have a couple of minutes to rinse off. Eyes
excepted.

I use sulfuric acid as a pickle when soldering silver, with a rinse bath
near by. For delicate pieces that I don't want to grab with tongs
(copper to avoid electroplating) I use my fingers. No ill effects if
rinsed in a minute or so. I use muriatic acid to clean copper and brass,
and as a flux for soldering galvanized iron. I also dunk my hands in it
to reveal any small skin breaks that would warn me not to handle
cyanide. (When a cyanide bath is available, it's handy for lightening
nitric-acid stains from skin, but one wants assurance that the skin
isn't broken.)

You are a total fuckin' loon, dude.

 

[Roy L. Fuchs]

It does indeed, with a positive copper tempco:

RHOt = 1.8x10^-8(1+0.0039(T-20) ohm-meters at T(C).

Yet you forget that the WIRE itself, not the ambient room temp has
to be maintained at said temperature, and THAT is the part that does
NOT happen.

Cold bearings probably have less friction.

You're an idiot to believe that. A DRY cold bearing MAY have
greater clearances, but slop can cause friction problems elsewhere.
If it is NOT a dry bearing, the grease used in it will most assuredly
be less mobile when cold.

Most cold things shrink,

So what? The bearing race would shrink as well.

so tolerances would increase.

A ball bearing is hardened steel, and it will NOT shrink
significantly in this scenario... at all.

Warming engine oil helps, but that's
a different story.

Grease is a petroleum distillate in most cases as well. even
synthetics thicken when cold.

Try again.

 

[Roy L. Fuchs]

Would YOU care to explain that further?

Nick

Look, dude. Take a car battery and a 100Watt 12V bulb.

Run it for hours on end. Much heat generated in the bulb... near
none generated in the battery.

Care to explain why you do not know this fact?

 

[[email protected]]

It is a well established warning on wet lead acid batteries that
dead shorts can cause explosions of the battery.

Would you have any evidence for this article of faith?

Nick

 

[Roy L. Fuchs]

The steel shaft probably shrinks less that the bronze bushing it rides in.

Damn! You may have actually gotten one right.

 

[Roy L. Fuchs]

Wow, somebody agrees with me

The Exide site says their ORB78DT84 auto battery can deliver 770
"cold cranking amps" for 30 seconds at 0 F at 1.2 volts per cell,
ie 7.2 volts at the terminals. That makes the internal resistance
about (12-7.2)/770 = 0.00623 ohms... 770^2x0.00623x30/3600x3.412
= 105 Btu, which might warm the battery up to 0+105/15 = 7 F...

Nick

The difference is negligible. The reason is that the wire does NOT
remain at the same temperature... AT ALL!

It NAY have a lower resistance at rest, but when used for carrying
current, it will most certainly be heating up, throwing your
assertions right out the window with it.

 

[jk]

If top posting is offensive to you don read it. Top posting or not,
is NOTHING more than a MINOR convention, but is not big deal. Being
an A-Hole about it is an whole other thing.

Aside from being top posted like that of a retarded Usenet newbie,
IAWTP.

If top posting is offensive to you don read it. Top posting or not,
is NOTHING more thank a MINOR convention, but is not big deal. Being
an A-Hole about it is an whole other thing.

The best way to manage cold batteries is to have them on a trickle
charger all night. Even a warmer blanket works.

Shorting them actually uses up what charge is available and doesn't
warm the battery enough to make it crank harder.

It is total myth.

If top posting is offensive to you don read it. Top posting or not,
is NOTHING more thank a MINOR convention, but is not big deal. Being
an A-Hole about it is an whole other thing.

jk

 

[jk]

From your own reference

"Unsurprisingly, different online communities differ on whether or not
top-posting is objectionable".

My own observation, "and some peole are jerks about it."

He claims to be an engineer too.

Your only claim to fame is that you are a top posting Usenet retard.

http://en.wikipedia.org/wiki/Top-posting

jk

 

[jk]

If you had been showered with full strength battery acid that
was not washed off for 1 minute, I assure you that it *would*
have burned your skin and damaged your cloths, to put it mildly.
(The clothes, incidentally, might not show a great deal of
damage immediately... but the next time they are run through the
washing machine they come out with more holes than not!)

The one time that happend to me, clearly, the threads were of a
different material in the warp and woof. It made a neat effect with
all these holes with the threads missing from one direction only.
jk

 

[repatch]

If it works, don't knock it. The attitude, "If I can't explain it, I can't
believe it" is more than a bit silly, don't you think?

I agree, and I'm not going to comment on whether it works or not.

That said, I would NEVER do such a thing. It's dangerous for numerous
reasons (big sparks under a hood are never good, grease can burn quite
easily).

TTYL

Back when we had

 

[Jerry Avins]

Roy L. Fuchs wrote:

... the heat generated causes the shellac on the mag wire to
liquify ...

Shellac? Where do you live?

Jerry

 

[Jerry Avins]

Roy L. Fuchs wrote:

...

A ball bearing is hardened steel, and it will NOT shrink
significantly in this scenario... at all.

...

Hardening doesn't reduce steel's coefficient of thermal expansion.

Jerry

 

[Jerry Avins]

Roy L. Fuchs wrote:

...

It NAY have a lower resistance at rest, but when used for carrying
current, it will most certainly be heating up, throwing your
assertions right out the window with it.

It has less rise over ambient when the weather is cold, that's all.

Jerry

 

[Jerry Avins]

Roy L. Fuchs wrote:

...

The problem is that you do not even know what you observed.

And from your remote armchair, you do? You seem like one of those who
say, "My mind is made up. Don't confuse me with facts."

Jerry

 

[Jerry Avins]

...



Good for you. I HAVE seen batteries that have exploded.

So have I. Did you miss "spontaneous"? A sustained /external/ short will
often explode one.

Jerry

 

[Roy L. Fuchs]

If top posting is offensive to you don read it. Top posting or not,
is NOTHING more than a MINOR convention, but is not big deal. Being
an A-Hole about it is an whole other thing.

Being a blatant, non conformist, abject fucking retard about it is an
entirely different thing as well, dumbfuck.

Fucking anarchistic, adolescent, mosh pit punk fucktards like you
are NOT going to get away with dumbing down the entire world to your
level of utter stupidity.

Pull your pants up, boy.

 

[Jerry Avins]

Would you have any evidence for this article of faith?

Been there. Seen it.

Jerry

 

[Roy L. Fuchs]

From your own reference

"Unsurprisingly, different online communities differ on whether or not
top-posting is objectionable".

Yeah... whoopie doo. Most of the article is correct. That fact that
it is publicly edited means that some fucktard not much different than
you contaminated the real facts with bullshit... yet again.

My own observation, "and some peole are jerks about it."

Go look in the mirror, retard boy.

If you would merely conform, and actually BONE UP a bit on Usenet,
instead of just blatantly abusing it like its some fucking BBS message
board, you MIGHT garner a clue before it is over.

Your own new reader defaults to the correct location.

You have to be a true retard to use a proper news reader yet still
get it wrong. D'OH!

 

[Floyd L. Davidson]

That's true only if you monitor individual battery voltages. (You can't
get at the cells.) In practice, the only measurement is of the total
voltage across the string. The batteries must be matched to support the
assumption that all voltages are the same and can be known from the sum.

You don't need to monitor eithr cell voltages or individual
battery voltages; you need to know what they are when the system
is adjusted (when it is all calibrated for charge current,
output current limiting, low voltage cutoff, float voltage,
etc.).

In other words you simply must have it adjusted to match the
batteries that are in use. Whether they are all exactly the
same, or some are new and some are old, or even if they are a
bit different.

We're discussing UPSs, not battery plants in general. Typically,
"periodic maintenance" amounts to response to failure.

If you don't know what we are discussing, how can you presume to
contribute?

 

[Roy L. Fuchs]

Roy L. Fuchs wrote:



Shellac? Where do you live?

Jerry

You obviously know nothing about the term conventions used in motor
manufacture or mag wire manufacture.